Multidisciplinary management of adult low grade gliomas.

BACKGROUND: Adult hemispheric low grade gliomas (LGG) cover a pathologic spectrum which has specific clinical, histological and molecular characteristics. The optimal management of these tumors is still a controversial topic in international literature. METHODS: We evaluated scientific papers from the literature (Medline and Cochrane Library to date) and we compared the results found there with our experience, trying to create a pattern of treatment of our own. RESULTS AND CONCLUSIONS: The advances in microsurgical and neuromonitoring techniques, as well as in neuroimaging, allow for a more aggressive resection of LGG with a significant improvement in overall survival and quality of life. The potential risks of the "wait and see" policy and the neurotoxicity of radiotherapy are challenged by the benefits of careful surgical resection and up-front chemotherapy. The present day treatment strategy, based on recent evidence, should include a maximal surgical resection when possible, with the full preservation of the patients ability, and delayed radiotherapy. The role of temozolomide in the management of LGG and the identification of the therapeutic modality with the best quality of life profile will be determined by ongoing trials. The further characterization of prognostic relevance of molecular markers and data from advanced imaging techniques needs an intensification of research and validation efforts. ABBREVIATIONS: LGG: low grade gliomas, WHO: World Health Organization, OS: overall survival, PFS: progression-free survival, MRI: Magnetic resonance imaging, MRS: Magnetic resonance spectroscopy, MPFS: malignant progression-free survival, rCBV: Relative Cerebral Blood Volume, QOL: quality of life, FLAIR: Fluid attenuated inversion recovery, MGMT: O6-methylguanine DNA methyltransferase enzyme, DSC MR imaging: Dynamic Susceptibility Contrast Perfusion MR imaging, 1H-MRS: Proton Magnetic Resonance Spectroscopy, IDH1: isocitrate dehydrogenase 1 gene, SPECT: Single-photon emission computed tomography, PET: Positron emission tomography, DTI-FT: Diffuse Tensor Imaging-fiber tracking technique, DES: direct electrical stimulation, EEG: Electroencephalography, EcoG: Electrocorticography, MEP: motor evoked potentials, EMG: Electromyography, AED: anti-epileptic drugs, TMZ: Temozolomide, EORTC: European Organization for Research and Treatment of Cancer, NCCTG: North Central Cancer Treatment Group, RTOG: Radiation Therapy Oncology Group, ECOG: Eastern Cooperative Oncology Group, EOR: extent of resection, Gy: Gray (unit), GyE: gray equivalent, RT: radiation therapy, IMRT: image-guided intensity modulated radiotherapy, FSRT: fractionated stereotactic radiotherapy, SRS: proton therapy or stereotactic radiosurgery, LET: high-linear energy transfer beams, RBE: relative biological effectiveness, CTCAE: Common Terminology Criteria for Adverse Events, PCV: procarbazine, lomustine, and vincristine chemotherapy.

Prevalence and functional consequence of PHOX2B mutations in neuroblastoma.

PHOX2B is a homeodomain-containing protein that is involved in the development of the peripheral nervous system and is the major disease gene for the rare congenital breathing disorder congenital central hypoventilation syndrome (CCHS). Germline PHOX2B alterations were also recently discovered in neuroblastoma cases with CCHS and/or Hirschsprung disease, but a comprehensive survey for mutational frequency and functional consequence has not been performed. We therefore studied a large panel of hereditary neuroblastomas to understand the frequency and functional effects of PHOX2B mutations. Three of 47 individuals with presumed genetic predisposition to neuroblastoma showed a germline PHOX2B mutation (6.4%). Mutations were also discovered in 2 of 30 human neuroblastoma-derived cell lines, but none of 86 primary tumors from patients with sporadically occurring neuroblastoma. The vast majority of primary tumors showed abundant PHOX2B mRNA expression relative to the remainder of the transcriptome. Consistent with its role as an important neurodevelopmental gene, forced overexpression of wild-type PHOX2B in neuroblastoma cell lines suppressed cell proliferation and synergized with all-trans retinoic acid to promote differentiation. Patient-derived mutant PHOX2B constructs retained the ability to suppress cellular proliferation, but were not able to promote differentiation or activate expression of a known PHOX2B target gene in vitro. These findings show that PHOX2B alterations are a rare cause of hereditary neuroblastoma, but disruption of this neurodevelopmental pathway can interfere with transcription-dependent terminal differentiation. These data also suggest that the genetics of neuroblastoma initiation are complex, and highlight genes involved in normal noradrenergic development as candidate predisposition genes.

Gabapentin as an adjunct to standard mood stabilizers in outpatients with mixed bipolar symptomatology.

Gabapentin is a new adjunctive medication to antiseizure therapies. Anecdotal evidence suggests that it may also help to alleviate mood symptoms in patients with bipolar illness. An open-label study examined the effects of adjunctive gabapentin in bipolar patients with mixed symptoms who had previously demonstrated only partial treatment responses. Mood ratings and side-effect profiles were followed weekly in 10 patients for 1 month. Decreases in Hamilton depression (P < 0.05) and Bech mania ratings (P < 0.01) were evident in the first week of treatment and were sustained. Potent early improvements were noted in early, middle, and late insomnia. The results suggest that gabapentin may be of benefit to bipolar patients who only partially respond to other mood stabilizers. A favorable side-effect profile and rapid action make this drug an attractive choice as an adjunctive therapy.

Impaired K(+) homeostasis and altered electrophysiological properties of post-traumatic hippocampal glia.

Traumatic brain injury (TBI) can be associated with memory impairment, cognitive deficits, or seizures, all of which can reflect altered hippocampal function. Whereas previous studies have focused on the involvement of neuronal loss in post-traumatic hippocampus, there has been relatively little understanding of changes in ionic homeostasis, failure of which can result in neuronal hyperexcitability and abnormal synchronization. Because glia play a crucial role in the homeostasis of the brain microenvironment, we investigated the effects of TBI on rat hippocampal glia. Using a fluid percussion injury (FPI) model and patch-clamp recordings from hippocampal slices, we have found impaired glial physiology 2 d after FPI. Electrophysiologically, we observed reduction in transient outward and inward K(+) currents. To assess the functional consequences of these glial changes, field potentials and extracellular K(+) activity were recorded in area CA3 during antidromic stimulation. An abnormal extracellular K(+) accumulation was observed in the post-traumatic hippocampal slices, accompanied by the appearance of CA3 afterdischarges. After pharmacological blockade of excitatory synapses and of K(+) inward currents, uninjured slices showed the same altered K(+) accumulation in the absence of abnormal neuronal activity. We suggest that TBI causes loss of K(+) conductance in hippocampal glia that results in the failure of glial K(+) homeostasis, which in turn promotes abnormal neuronal function. These findings provide a new potential mechanistic link between traumatic brain injury and subsequent development of disorders such as memory loss, cognitive decline, seizures, and epilepsy.

P-selectin blockade following fluid-percussion injury: behavioral and immunochemical sequelae.

Traumatic brain injury (TBI) can cause polymorphonuclear leukocyte (PMN) migration into brain parenchyma, mediating various cytodestructive mechanisms. We examined the effect of blocking leukocyte/endothelial cell adhesion molecules (CAMs) on the anatomic and behavioral sequelae in lateral fluid-percussion injury in rats. Monoclonal antibodies (MAb) directed against a functional (PB1.3) or nonfunctional (PNB1.6) epitope on endothelial P-selectin were used as treatments. Subjects were tested in the Morris water maze (MWM) at 7 and 14 days postinjury then immunohistochemistry was performed using antibodies that recognize ChAT, GFAP and OX-42. A second set of animals underwent myeloperoxidase (MPO) assay in the brain parenchyma and a third set was used to examine neutrophil migration using the MAb RP-3. Time in quadrant, but not escape latency or proximity improved with PB1.3 (p < 0.05). Similarly, PB1.3 reduced MPO levels after injury (p < 0.05), in the ipsilateral cortex. No significant difference occurred in neutrophil counts in cortex, corpus callosum, hippocampus, and thalamus between injured only rats and injured rats treated with PB1.3. Quantitative analysis of cholinergic cells in the medial septum showed a protective effect by PB1.3. Densitometry readings of GFAP and OX-42 immunolabeling revealed no discernible differences between the treated and untreated injured rats. Qualitatively, there was no difference in microglia or astrocyte response to treatment. Treatment with P-selectin blockade in brain-injured rats may reduce PMN migration into brain, help preserve cholinergic immunolabeling of medial septal nucleus neurons, and may alleviate mnemonic deficits.

A new model of the blood--brain barrier: co-culture of neuronal, endothelial and glial cells under dynamic conditions.

Developing in vitro blood-brain barrier (BBB) models that closely mimic the natural state is important for theoretical and practical applications, including drug development. We previously developed an in vitro BBB model based on co-culturing endothelial cells with glia in the presence of flow on hollow fiber tube culture substrates. We now report that this dynamic in vitro BBB (DIV-BBB) can be successfully used to co-culture differentiated serotonergic neurons in the presence of a BBB. These neurons demonstrated fluoxetine-sensitive serotonin (5HT) uptake and depolarization-induced release of [3H]5HT. Our results demonstrate that the DIV-BBB is a suitable model for culturing of neurons in a quasi-physiological microenvironment and in the presence of a high-resistance, stereoselective BBB.

Selective loss of hippocampal long-term potentiation, but not depression, following fluid percussion injury.

We investigated the early effects of in vivo fluid percussion injury (FPI) on hippocampal synaptic potentials and excitability. In vitro field potential recordings and immunocytochemistry were performed in the CA1 region in slices from naïve, post-FPI, or sham-operated rats. The following electrophysiological and morphological parameters were affected following FPI: (1) threshold for population spike generation was increased suggesting that post-FPI neurons were hypoexcitable; (2) long-term potentiation (LTP) could not be induced in injured hippocampi; (3) GFAP and inducible NO synthase (iNOS) immunoreactivity were enhanced post-FPI; and (4) following injury, synaptophysin immunoreactivity was enhanced in CA1 stratum radiatum. The effects of FPI on synaptic plasticity were LTP-specific, since long-term depression (LTD) could be equally induced and maintained in post-FPI, sham-operated and control slices. Sham-operated slices were characterized by synaptic excitability indistinguishable from naïve controls, but displayed decreased ability for LTP production and expressed high levels of iNOS. We conclude that FPI causes a selective loss of LTP, possibly due to a previous potentiation induced by trauma as reflected by the increased expression of synaptic proteins. Sham surgical procedures were, however, not without effects on long-term potentiation itself; the latter effects appear to be mediated by an increased production of NO. Our study demonstrates for the first time that hippocampal slices can be used to investigate the correlates of in vivo FPI. Furthermore, we describe LTP-specific deficits in post-traumatic brain injury, suggesting that FPI can selectively erase one of the two main NMDA-dependent forms of synaptic plasticity in the hippocampus.

Adaptation of the fluid percussion injury model to the mouse.

Fluid percussion injury (FPI) is a well-characterized experimental model of traumatic brain injury (TBI) in the rat. Many pathophysiologic consequences and mechanisms of recovery after TBI rely on neurochemical pathways that can be examined in genetically altered mice. Therefore, FPI applied to mice may be a useful experimental tool to investigate TBI at the molecular level. In the present study, we establish FPI as a viable model of TBI in the mouse by characterizing acute neurological, histopathological, and behavioral changes. Right-sided parasagittal FPI or sham treatment was administered in male C57BL/6 mice. Acute neurological evaluation revealed righting reflexes in the injured animals (p < 0.001). Deficits in spatial learning and memory were observed in the Morris water maze (MWM) 5 and 6 days after injury. A novel MWM data analysis protocol is described. The injured group (n = 18) demonstrated impaired performance in the MWM during acquisition (p < 0.05) and probe trials (p < 0.025) compared to sham animals (n = 16). At 7 days postinjury, glial fibrillary acidic protein immunohistochemistry revealed intense cortical, callosal, and hippocampal gliosis. The modified Gallyas silver degeneration stain consistently labeled cell bodies and terminals throughout the ipsilateral cortex, axons in the gray matter-white matter interface above the corpus callosum and within the corpus callosum bilaterally, and terminals and fibers in the thalamus bilaterally. Additionally, the mouse FPI model described is immediately employable in labs already using the FPI rat model with no modifications to a pre-existing FPI apparatus.

Humoral immune responses against Plasmodium vivax MSP1 in humans living in a malaria endemic area in Flores, Indonesia.

The aim of this study was to evaluate the relationship among age, parasitemia status, spleen size, hematocrit, and antibody levels to Plasmodium vivax merozoite surface protein 1 (MSP1) in individuals chronically exposed to P. vivax. Subjects were recruited from the population of three adjacent villages on the Island of Flores in Indonesia where malaria transmission is hyperendemic and tropical splenomegaly syndrome is highly prevalent. Subjects were evaluated for spleen size, hematocrit, presence of parasitemia, and presence of antibodies to a recombinant peptide consisting of 90 amino acids from the carboxy terminus of MSP1. Fifty-seven percent of 2-4 year olds, 45% of 5-9 years old, and 7% of > or = 15 years old were parasitemic; 99% of the > or = 15 years old had splenomegaly, and 31% of them had Hackett 4 or 5 spleens. The frequency of antibody positivity to MSP1 antigen in ELISA increased with age reaching a maximum of 89% in > or = 20 years old. The frequency of antibody positivity to MSPI also increased with spleen size, and with a decline in the prevalence of parasitemia.

Malaria DNA vaccines in Aotus monkeys.

In preparation for the development of DNA vaccines designed to produce protective antibodies against Plasmodium falciparum antigens (Ag), we conducted studies to optimize antibody responses in Aotus monkeys after immunization with the P. yoelli circumsporozoite (CSP) DNA vaccine. We demonstrate in Aotus monkeys that an intradermal route of immunization with a PyCSP plasmid DNA vaccine generates antibody responses equivalent to a multiple antigen peptide/adjuvant based vaccine, and that these data support the use of the intradermal route for initial studies of the efficacy of DNA vaccines in inducing protective antibodies against P. falciparum antigens in Aotus monkeys.

Quantitative microscopy of hepatic changes induced by phenethyl isothiocyanate in Fischer-344 rats fed either a cereal-based diet or a purified diet.

Hepatic changes induced by phenethyl isothiocyanate (PEITC) in the liver of rats were determined by quantitative microscopy. Groups of male Fischer-344 rats were fed either a standard, cereal-based diet (Wayne rodent meal) or a purified diet (AIN-76A) containing PEITC at concentrations of 0.75 and 6.0 mmol/kg for 13 wk. Severe hepatic lipidosis was observed in control rats fed the purified diet. Addition of PEITC to the purified diet significantly reduced lipid content in hepatocytes. In contrast, lipid content in the liver of the rats fed the cereal-based diet containing PEITC was greater than in control rats maintained on the same diet. In addition, dose-related reductions in hepatocyte, lipid droplet, peroxisome, and mitochondrial volumes were observed in PEITC-treated rats fed the cereal-based diet. These results indicate that PEITC exerts differential effects on the liver of rats fed either the cereal-based or purified diet.

Fluid percussion injury causes loss of forebrain choline acetyltransferase and nerve growth factor receptor immunoreactive cells in the rat.

Memory dysfunction is a common sequela of human traumatic brain injury (TBI). Cholinergic forebrain neurons are recognized for their role in memory. We tested the hypothesis that forebrain cholinergic neurons are vulnerable to fluid percussion injury (FPI), a model of human TBI. Rodents were subjected to a moderate parasagittal FPI, sham injury, or fimbria/fornix axotomy and then killed 10 days after the procedure. Additional animals underwent FPI or sham injury and were killed 7, 14, and 28 days after the procedure. Neurons in the medial septal nucleus and vertical limb of the nucleus of the diagonal band of Broca were identified and quantitated using choline acetyltransferase (ChAT) and low affinity nerve growth factor receptor (NGF-R) immunohistochemistry. Our results showed a significant decrease in ChAT (17% +/- 5%) and NGF-R (24% +/- 8%) immunoreactive cells in FPI animals killed after 10 days when compared to sham-injured animals. Animals undergoing fimbria/fornix axotomy showed a greater reduction in ChAT (53% +/- 13%) and NGF-R (55% +/- 5%) immunoreactive cells 10 days postaxotomy. The number of ChAT and NGF-R immunoreactive neurons was reduced at all time points. However, statistical significance was present 10 and 14 days postinjury for ChAT immunoreactive neurons and 10 days only for NGF-R immunoreactive neurons. These studies have shown that FPI produces transient loss of ChAT and NGF-R immunoreactive neurons.

Expression and transfer of engineered catabolic pathways harbored by Pseudomonas spp. introduced into activated sludge microcosms.

Two genetically engineered microorganisms (GEMs), Pseudomonas sp. strain B13 FR1(pFRC20P) (FR120) and Pseudomonas putida KT2440(pWWO-EB62) (EB62), were introduced into activated sludge microcosms that had the level of aeration, nutrient makeup, and microbial community structure of activated sludge reactors. FR120 contains an experimentally assembled ortho cleavage route for simultaneous degradation of 3-chlorobenzoate (3CB) and 4-methyl benzoate (4MB); EB62 contains a derivative TOL plasmid-encoded degradative pathway for toluene experimentally evolved so that it additionally processes 4-ethyl benzoate (4EB). Experiments assessed survival of the GEMs, their ability to degrade target substrates, and lateral transfer of plasmid-encoded recombinant DNA. GEMs added at initial densities of 10(6) to 10(7) bacteria per ml of activated sludge declined to stable population densities of 10(4) to 10(5) bacteria per ml. FR120 degraded combinations of 3CB and 4MB (1 mM each) following 3 days of adaptation in the microcosms. Indigenous microorganisms required an 8-day adaptation period before degradation of 4MB was observed; 3CB was degraded only after the concentration of 4MB was much reduced. The indigenous microbial community was killed when both compounds were present at concentrations of 4.0 mM. However, in parallel microcosms containing FR120, the microbial community maintained a normal density of viable cells. Indigenous microbes readily degraded 4EB (2 mM), and EB62 did not significantly increase the observed rate of degradation. In filter matings, transfer of pFRC20P, which specifies mobilization but not transfer functions, from FR120 to P. putida UWC1 was not detectable (< 10(-7) transconjugants per donor cell).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood-brain barrier permeability is not altered by allograft or xenograft fetal neural cell suspension grafts.

Alterations in blood-brain barrier (BBB) function after brain grafting seem dependent on the donor phenotype and possibly on the grafting technique. Intracerebral blood grafts of nonneural tissue permanently disrupt the host BBB, while fetal neural block grafts probably do not. Cell suspensions, an alternative technique in brain grafting, disrupt the extracellular matrix of the graft. Fetal cell suspension allografts appear to form a functional BBB. We confirm and extend this finding to include fetal neural xenografts. Allograft and xenograft fetal neural cell suspensions were intracerebrally injected, and the BBB was examined using intravenous horseradish peroxidase (HRP). Neither graft type showed disruption of the BBB at the graft site from 2 weeks to more than 6 months after grafting. Vascular supply was prominent at all time points. Xenograft survival was improved with cyclosporine, yet cyclosporine did not affect BBB permeability. Cyclosporine did not interfere with repair of the BBB after simple brain trauma was induced by a control injection of saline. We conclude that fetal allograft and xenograft neural cell suspensions rapidly form and maintain a BBB impermeable to intravenous HRP.

Substrate specificity of the Escherichia coli maltodextrin transport system and its component proteins.

Maltooligosaccharides up to maltoheptaose are transported by the maltodextrin transport system of Escherichia coli. The overall substrate specificity of the transport system was investigated by using 15 maltodextrin analogues with various modifications at the reducing end of the oligosaccharides as competing substrates. The binding interaction of the analogues with maltoporin in the outer membrane and the periplasmic maltose-binding protein, the two protein components of the transport system with known specificity for maltodextrins, was also investigated. All analogues containing several alpha, 1----4-glucosyl linkages were bound with high affinity by maltoporin and maltose-binding protein, regardless of O-methyl, O-nitrophenyl, beta-glucosyl or beta-fructosyl substitutions at the reducing end of the dextrins. Introduction of a negative charge or lack of a ring structure at the reducing end were also ineffective in abolishing binding by these two proteins. These results suggest that the structure of the reducing glucose is not important in the binding specificity of maltoporin or maltose-binding protein. However, the high affinity of these proteins for analogues was not in itself sufficient for recognition by the transport system overall. Maltohexaitol, 4-nitrophenyl alpha-maltotetraoside and 4-beta-D-maltopentaosyl-D-glucopyranose were bound with the same affinity as comparable maltodextrins by both maltoporin and maltose-binding protein but were poorly recognized by the transport system. These results suggest that another, yet uninvestigated component of the transport system has a more restricted specificity towards changes at the reducing end of the maltodextrin molecule.